/* Cookie Library -- "Night of the Living Cookie" Version (25-Jul-96)

  Written by:  Bill Dortch, hIdaho Design <bdortch@hidaho.com>
  The following functions are released to the public domain.

  This version takes a more aggressive approach to deleting
  cookies.  Previous versions set the expiration date to one
  millisecond prior to the current time; however, this method
  did not work in Netscape 2.02 (though it does in earlier and
  later versions), resulting in "zombie" cookies that would not
  die.  DeleteCookie now sets the expiration date to the earliest
  usable date (one second into 1970), and sets the cookie's value
  to null for good measure.

  Also, this version adds optional path and domain parameters to
  the DeleteCookie function.  If you specify a path and/or domain
  when creating (setting) a cookie**, you must specify the same
  path/domain when deleting it, or deletion will not occur.

  The FixCookieDate function must now be called explicitly to
  correct for the 2.x Mac date bug.  This function should be
  called *once* after a Date object is created and before it
  is passed (as an expiration date) to SetCookie.  Because the
  Mac date bug affects all dates, not just those passed to
  SetCookie, you might want to make it a habit to call
  FixCookieDate any time you create a new Date object:

    var theDate = new Date();
    FixCookieDate (theDate);

  Calling FixCookieDate has no effect on platforms other than
  the Mac, so there is no need to determine the user's platform
  prior to calling it.

  This version also incorporates several minor coding improvements.

  **Note that it is possible to set multiple cookies with the same
  name but different (nested) paths.  For example:

    SetCookie ("color","red",null,"/outer");
    SetCookie ("color","blue",null,"/outer/inner");

  However, GetCookie cannot distinguish between these and will return
  the first cookie that matches a given name.  It is therefore
  recommended that you *not* use the same name for cookies with
  different paths.  (Bear in mind that there is *always* a path
  associated with a cookie; if you don't explicitly specify one,
  the path of the setting document is used.)
  
  Revision History:

    "Toss Your Cookies" Version (22-Mar-96)
      - Added FixCookieDate() function to correct for Mac date bug

    "Second Helping" Version (21-Jan-96)
      - Added path, domain and secure parameters to SetCookie
      - Replaced home-rolled encode/decode functions with Netscape's
        new (then) escape and unescape functions

    "Free Cookies" Version (December 95)


  For information on the significance of cookie parameters, and
  and on cookies in general, please refer to the official cookie
  spec, at:

      http:www.netscape.com/newsref/std/cookie_spec.html    

****************************************************************** */

/* "Internal" function to return the decoded value of a cookie */
function getCookieVal (offset) {
  var endstr = document.cookie.indexOf (";", offset);
  if (endstr == -1) {
    endstr = document.cookie.length;
  }
  return unescape(document.cookie.substring(offset, endstr));
}

/* Function to correct for 2.x Mac date bug.  Call this function to
  fix a date object prior to passing it to SetCookie.
    IMPORTANT:  This function should only be called *once* for
    any given date object!  See example at the end of this document. */
function FixCookieDate (date) {
  var base = new Date(0);
  var skew = base.getTime(); // dawn of (Unix) time - should be 0
  if (skew > 0) {       // except on the Mac - ahead of its time
    date.setTime(date.getTime() - skew);
  }
}

/* Function to return the value of the cookie specified by "name".
  name - String object containing the cookie name.
    returns - String object containing the cookie value, or null if
    the cookie does not exist. */
function GetCookie (name) {
  var temp = name + "=";
  var tempLen = temp.length;
  var cookieLen = document.cookie.length;
  var i = 0;
  while (i < cookieLen) {
    var j = i + tempLen;
    if (document.cookie.substring(i, j) == temp) {
      return getCookieVal(j);
    }
      i = document.cookie.indexOf(" ", i) + 1;
      if (i == 0) break; 
  }
  return null;
}

/*  Function to create or update a cookie.
    name - String object containing the cookie name.
    value - String object containing the cookie value.  May contain
      any valid string characters.
    [expiresDate] - Date object containing the expiration data of the cookie.  If
      omitted or null, expires the cookie at the end of the current session.
    [path] - String object indicating the path for which the cookie is valid.
      If omitted or null, uses the path of the calling document.
    [domain] - String object indicating the domain for which the cookie is
      valid.  If omitted or null, uses the domain of the calling document.
    [secure] - Boolean (true/false) value indicating whether cookie transmission
      requires a secure channel (HTTPS).  

  The first two parameters are required.  The others, if supplied, must
  be passed in the order listed above.  To omit an unused optional field,
  use null as a place holder.  For example, to call SetCookie using name,
  value and path, you would code:
  
    SetCookie ("myCookieName", "myCookieValue", null, "/");
  
  Note that trailing omitted parameters do not require a placeholder.
  
  To set a secure cookie for path "/myPath", that expires after the
  current session, you might code:

    SetCookie (myCookieVar, cookieValueVar, null, "/myPath", null, true); */
function SetCookie (name,value,expiresDate,path,domain,secure) {
  document.cookie = name + "=" + escape (value) +
    ((expiresDate) ? "; expires=" + expiresDate.toGMTString() : "") +
    ((path) ? "; path=" + path : "") +
    ((domain) ? "; domain=" + domain : "") +
    ((secure) ? "; secure" : "");
}

/*  Function to delete a cookie. (Sets expiration date to start of epoch)
    name -   String object containing the cookie name
    path -   String object containing the path of the cookie to delete.  This MUST
             be the same as the path used to create the cookie, or null/omitted if
             no path was specified when creating the cookie.
    domain - String object containing the domain of the cookie to delete.  This MUST
             be the same as the domain used to create the cookie, or null/omitted if
             no domain was specified when creating the cookie. */
function DeleteCookie (name,path,domain) {
  if (GetCookie(name)) {
    document.cookie = name + "=" +
      ((path) ? "; path=" + path : "") +
      ((domain) ? "; domain=" + domain : "") +
      "; expires=Thu, 01-Jan-70 00:00:01 GMT";
  }
}


// Calling examples:
//  var expdate = new Date ();
//  FixCookieDate (expdate); // Correct for Mac date bug - call only once for given Date object!
//  expdate.setTime (expdate.getTime() + (24 * 60 * 60 * 1000)); // 24 hrs from now 
//  SetCookie ("ccpath", "http://www.webbwoman.com/articles/", expdate);
//  SetCookie ("ccname", "WebWoman", expdate);
//  SetCookie ("tempvar", "This is a temporary cookie.");
//  SetCookie ("ubiquitous", "This cookie will work anywhere in this domain",null,"/");
//  SetCookie ("paranoid", "This cookie requires secure communications",expdate,"/",null,true);
//  SetCookie ("goner", "This cookie must die!");
//  document.write (document.cookie + "<br>");
//  DeleteCookie ("goner");
//  document.write (document.cookie + "<br>");
//  document.write ("ccpath = " + GetCookie("ccpath") + "<br>");
//  document.write ("ccname = " + GetCookie("ccname") + "<br>");
//  document.write ("tempvar = " + GetCookie("tempvar") + "<br>");